The Ketchum keystone. [volume] (Ketchum, Idaho) 1885-1899, 1887-10-15
FACTS ABOUT THE SEA.
Youths Companion.


The sea is the reservoir into
which run all the rivers Of the world.
Ii is the cistern which finally catch
es all the rain that falls, not only
upon its own surface, but upon the
surface of the land and upon the
roofs Of our houses. All this water
is removed again by evaporation as
fast as it is supplied. 1t is esti-
mated that every year layer of
the entire sea, fourteen feet thick
is taken up into the clouds. This
vapor is fresh, and if all the water
could be removed in the same way
and none of it returned, it is cal
culated that there would be left a
layer of pure salt $50 feet thick on
the bed of the Atlantic.
This is upon the supposition that
three feet depth of water contains
one inch depth of salt, and that
the average depth of the ocean is
three miles.
At the depth of about $500 feet
the temperature is uniform, vary
ing but a trifle between the poles
and the equator. The colder water
is below. 1t is reported that in
many deep bays on the coast OF
of Norway, the water often begins
to freeze at the bottom before il
does at the surface.
At this depth waves are not felt
Waves do not travel-that is, the
water does not move forward, al
though it seems to do so; it stays
in the same place. The rising and
falling moves on.
We measure waves by their height
and by the distance from crest to
crest. In deep water this latter
distance is about fifteen times the
height of the waves. In shallow
water the proportion is less, and
this makes choppy sea.
The force of waves is in proper.
tior to their height. 1t is said that
the sea strikes on Bell Rock with
the force of seventeen tons for each
square yard.
The pressure Of the water in
creases as we 60 down. At The
depth of a mile this pressure j:
reckoned at more than a ton to th'
square inch that is, more than 13;
times the pressure of the atmos
pherc.
TO get correct sounding in deel
water is difficult. A shot weighing
thirty pounds carries down the line
Through this sinker a hole is bored
and through the hole is passed 1
rod of iron which moves easily
back and forth. In the end of th'
bar cup is dug out, and the inside
is coated with lard. The bar j.
made fast to the line and slim!
holds the shot on.
When the bar, which extends be
low the shot, touches the bottom
the sling unhooks and the sho
slides off. The cup in the end o
the bar holds some of the sand, o
whatever may be on the bottom
and cover shuts over the cup t.
keep the water from washing TIN
sand out. In this way we learr
the character of the deep sea bot
tom. 1t will be seen at once tha
we can know the depression of tn
bottom of the ocean more easil,
and more accurately than we cal
learn the elevation Of the land. A!
a consequence we have better to
biographical map of much of tha
surface than we have of the con
tinents.
The depth of the sea present
some interesting considerations. |
the Atlantic were lowered 500.
feet, it would be reduced to half it,
present width. If it were lowered
a little more than three miles, ther
would be dry land all the way from
Newfoundland to Ireland. If tn
Mediterranean were lowered 66
feet, Africa would be joined to Italy
and three separate seas would re
main.